Techniques involving nuclear magnetic resonance (NMR) have been widely adopted for use in applications such as spectroscopy and medical diagnosis. Nuclear magnetic resonance imaging (MRI) is widely used such as for imaging of the head, neck, abdomen, or extremities of an imaging subject. Generally, an MRI system includes a powerful bias magnet arranged to induce a static magnetic field along a specified axial direction. Gradients in the magnetic field can be induced as a function of spatial position to facilitate spatial localization of received signals. A spin axis of protons within the species being interrogated aligns with the applied field. A radio-frequency (RF) pulse is generally used to perturb the net spin polarization of the protons in a manner causing precession back to a state aligned with the applied magnetic field. Relaxation of the perturbed protons can be detected via coupling to a tuned RF receiving loop (e.g., a “receive coil”). In one approach, transmission of the RF pulse can be accomplished using one or more loop structures (e.g., a “transmit RF coil”) located in the same housing as the bias magnet. Such a transmit RF coil located in or nearby a housing of the bias magnet can be referred to as a “built-in body coil.”